Stability evaluation of vaccines
The stability of vaccines has a major impact on the success of immunization programmes worldwide. As part of its efforts to assure vaccine quality, WHO has acknowledged the importance of clearly defining the stability characteristics of a vaccine and emphasizes the role of national regulatory authorities in overall vaccine evaluation.
The temperature sensitivity of vaccine characteristics, particularly potency, led to the development of stage and cold chain requirements for all vaccines. In the 1980s and the beginning of the 1990s, a major WHO focus was on thermostability testing as measured by potency assays, as part of lot release. More recently, guidance has addressed the importance of studies performed under real storage conditions, real time and other relevant environmental factors. In addition, the WHO guidelines for nonclinical and clinical evaluation of vaccines, stress a need for stability data to support clinical trial approval. However, until now there has been no comprehensive guidance document available which deals with the stability evaluation of vaccines at different stages of vaccine development, production, licensing, lot release and post-licensing studies.